Cars may often be disabled because of tire damage, fuel exhaustion or engine malfunction while they are being driven. On the other hand, the disabled cars cannot drive to a gas station for fueling, or to a repair shop for repairing. In these situations, the only way is to use a tow truck to move the disabled cars. However, it takes time to wait for the tow truck, and the tow truck may be even unable to arrive due to a traffic jam. As a result, the disabled cars may affect the normal passage on the road for a long time, which thus may cause great inconvenience to people's life and travel.